Work will be directed towards 3 goals. 1) A study of the factors involved in compensatory renal hypertrophy will be made. Major consideration will be to test the work hypothesis of hypertrophy. Biochemical (RNA and DNA content) and functional (GRF and RBF) growth will be measured in rats with unilateral ureteral obstruction. 2) To study the interaction at a renal level between angiotensin and ADH. Water loaded, alcohol anesthetized rats will be challenged with test doses of ADH. Measurements of GFR, RPF, urine volume and osmololity will be made following ADH. These results will be compared to that obtained after ADH is administered to rats given either angiotensin II or the angiotensin blocker, saralasin. 3) We will determine what role if any angiotensin plays in the central regulation of renin, ADH, ACTH and aldosterone secretion. Dogs will be prepared with special cannulae implanted into the lateral ventricle of the brain. They will also have the carotid arteries exteriorized so that arterial blood can be sampled easily and blood pressure determined. Hormone levels will be determined before and after ventricular infusion of angiotensin and angiotensin blocker. BIBLIOGRAPHIC REFERENCES: Sottuirai, V.S., R.L. Malvin, L.F. Allard and W.C. Bigelow, A Biological Standard for Electron Microprobe Analysis of Intracellular Sodium Concentration. J. Hist. and Cytochem. 24:749-751, 1976. Northrup, T.E. and R.L. Malvin., Cellular Hypertrophy and Renal Function During Compensatory Renal Growth. Am. J. Physiol, 231:1191-1195, 1976.